Degradable Metal Barrier For Downhole Screens

ABSTRACT

A method and system for temporarily preventing fluid flow through a screen assembly installed in a wellbore can include a screen assembly interconnected in a tubing string. Components of the screen assembly can include a base pipe, one or more filter layers, an optional drainage layer(s), with flow paths through each of the components. A degradable metal barrier can be applied to at least one of the components, which thereby temporarily prevents fluid flow through the flow paths, and temporarily provides pressure isolation radially between an interior and an exterior of the screen assembly. Degradation of the metal barrier can allow fluid and pressure communication radially between the interior and the exterior of the screen assembly.

TECHNICAL FIELD

The present disclosure generally relates to oilfield equipment and, in particular, to downhole tools, hydrocarbon production and related systems, and a metal barrier that can be applied to a downhole screen assembly. More particularly still, the present disclosure relates to systems and methods for applying the metal barrier to the downhole screen assembly prior to installation of the screen assembly in a wellbore, and after installation, the barrier can be removed by dissolving or otherwise degrading the barrier.

BACKGROUND

In the process of completing an oil or gas well, a tubing string can be run downhole and used to communicate produced hydrocarbon fluids from a subsurface formation to the surface. Typically, this tubing string can be coupled to a screen assembly that controls and limits debris, such as gravel, sand, and other particulate matter, from entering the tubing string as the fluid passes through the screen assembly.

The screen assembly generally includes a filter in the form of a screen with multiple entry points (or flow paths) at which the produced fluid (liquid and/or gas) passes through the screen. The screen is generally cylindrical and can be positioned adjacent or in proximity to an inflow control device (ICD), which can regulate flow of the produced fluid after the produced fluid passes through a flow path of the screen. These flow paths can be small to facilitate filtering of the produced fluid as it flows through the screen into the tubing string. Unfortunately, during installation of the screen assembly into a wellbore, the small flow paths can be plugged by mud, debris, and various other materials in the wellbore. The screen can also be damaged by impacts and other physical abuse. This plugging of the flow paths or damage to the screen and/or screen assembly can reduce the flow rate through the screen assembly during subsequent wellbore operations.

Therefore, it will be readily appreciated that improvements in the arts of protecting screen assemblies during installation in a wellbore are continually needed.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure. In the drawings, like reference numbers may indicate identical or functionally similar elements. Embodiments are described in detail hereinafter with reference to the accompanying figures, in which:

FIG. 1 is a representative partial cross-sectional view of a marine-based well system with one or more screen assemblies according to an embodiment, with the screen assemblies installed in a wellbore;

FIG. 2 is a representative partial cross-sectional view of an embodiment of a screen assembly, which can utilize principles of the present disclosure, positioned in a portion of the wellbore;

FIG. 3 is a representative partial cross-sectional view of the screen assembly initially installed in the wellbore which includes a degradable metal barrier with little to no degradation;

FIG. 4 is a representative partial cross-sectional view of the screen assembly after the degradable metal barrier is degraded;

FIG. 5 is a representative partial cross-sectional view of another embodiment of the screen assembly;

FIG. 6 is a representative partial cross-sectional view of yet another embodiment of the screen assembly;

FIG. 7 is a representative partial cross-sectional view of yet another embodiment of the screen assembly positioned in a gravel pack in the wellbore;

FIG. 8 is a representative exploded cross-sectional view of layers of an embodiment of the screen assembly.

DETAILED DESCRIPTION OF THE DISCLOSURE

The disclosure may repeat reference numerals and/or letters in the various examples or Figures. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as beneath, below, lower, above, upper, uphole, downhole, upstream, downstream, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure, the uphole direction being toward the surface of the wellbore, the downhole direction being toward the toe of the wellbore. Unless otherwise stated, the spatially relative terms are intended to encompass different orientations of the apparatus in use or operation in addition to the orientation depicted in the Figures. For example, if an apparatus in the Figures is turned over, elements described as being “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Moreover even though a Figure may depict a horizontal wellbore or a vertical wellbore, unless indicated otherwise, it should be understood by those skilled in the art that the apparatus according to the present disclosure is equally well suited for use in wellbores having other orientations including vertical wellbores, slanted wellbores, multilateral wellbores or the like. Likewise, unless otherwise noted, even though a Figure may depict an offshore operation, it should be understood by those skilled in the art that the method and/or system according to the present disclosure is equally well suited for use in onshore operations and vice-versa. Further, unless otherwise noted, even though a Figure may depict a cased hole, it should be understood by those skilled in the art that the method and/or system according to the present disclosure is equally well suited for use in open hole operations.

As used herein, the words “comprise,” “have,” “include,” and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods also can “consist essentially of” or “consist of” the various components and steps. It should also be understood that, as used herein, “first,” “second,” and “third,” are assigned arbitrarily and are merely intended to differentiate between two or more objects, etc., as the case may be, and does not indicate any sequence. Furthermore, it is to be understood that the mere use of the word “first” does not require that there be any “second,” and the mere use of the word “second” does not require that there be any “first” or “third,” etc.

As used herein, the term “degradable” and all of its grammatical variants (e.g., “degrade,” “degradation,” “degrading,” “dissolve,” dissolving,” “dissolution,” “corrode,” “corrodible,” “corrosion,” “erode,” “erosion,” and the like) refers to the dissolution or chemical conversion of solid materials such that reduced-mass solid end products by at least one of solubilization, hydrolytic degradation, biologically formed entities (e.g., bacteria or enzymes), chemical reactions (including electrochemical and galvanic reactions), thermal reactions, or reactions induced by radiation. In complete degradation, no solid end products result. In some instances, the degradation of the material may be sufficient for the mechanical properties of the material to be reduced to a point that the material no longer maintains its integrity and, in essence, falls apart or sloughs off to its surroundings. The conditions for degradation are generally wellbore conditions where an external stimulus may be used to initiate or affect the rate of degradation. For example, the pH of the fluid that interacts with the material may be changed by introduction of an acid or a base. The term “wellbore environment” includes both naturally occurring wellbore environments and materials or fluids introduced into the wellbore. It should also be understood that naturally occurring wellbore fluids can be used to degrade the material without requiring introduction of further materials into the wellbore.

The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

Generally, this disclosure provides a method and system for temporarily preventing fluid flow and pressure communication radially between and interior and an exterior of a screen assembly until the screen assembly is installed in a wellbore. A degradable metal barrier can be applied to components (e.g. base pipe, drainage layer, filter layer, shroud, etc.) of the screen assembly which can prevent fluid flow and pressure communication between and an interior and an exterior of the screen assembly until the barrier is degraded downhole. After installation of the screen assembly in the wellbore, the degradable metal barrier can be degraded by various means (e.g. corrosion, erosion, dissolution, chemical reactions, thermal reactions, etc.) such that the barrier is removed and fluid and pressure communication is allowed radially through the screen assembly. The degradable metal barrier can prevent (or at least minimize) clogging of the screen assembly during installation, and allow the screen assembly to be used for washing and gravel pack operations without needing a separate wash pipe. When the barrier is removed by degradation, the screen can be used during production operations by retaining gravel pack sand while filtering wellbore fluids that flow from the earthen formation into the production tubing string.

Referring to FIG. 1, upper and lower completion assemblies 60, 42 can be installed in a wellbore 38 from an offshore oil and/or gas platform 10. A semi-submersible platform 12 can be positioned over a submerged earthen formation 14 located below a sea floor 16. A subsea conduit 18 can extend from a deck 20 of the platform 12 to a subsea wellhead 22, including blowout preventers 24. The platform 12 can have a hoisting apparatus 26, a derrick 28, a travel block 30, a hook 32, and a swivel 34 for raising and lowering pipe strings, such as a substantially tubular, axially extending tubing string 36.

A wellbore 38 can extend through the earthen formation 14 and can have a casing string 40 cemented therein. The lower completion assembly 42 may be positioned in a substantially horizontal portion of the wellbore 38. The lower completion assembly 42 can include one or more screen assemblies 48, 52 and 56, and various other components, such as a latch subassembly 44, one or more packers 46 and 58, one or more centralizers 50 and 54, etc. The upper completion assembly 60 can be coupled to a lower end of the tubing string 36 and can include various components such as one or more packers 62 and 66, an expansion joint 64, a flow control module 68, an anchor assembly 70, a latch subassembly 72, etc. One or more communication cables (such as an electric cable 74 that passes through the packers 62, 66) may be provided and extend from the upper completion assembly 60 to the surface through an annulus 75. The latch subassembly 44 can couple to the latch subassembly 72, thereby coupling the upper and lower completion assemblies 60, 42 together.

A wash pipe (not shown) may be connected to a work string with a cross-over setting tool (not shown). In this configuration, removing the wash pipe after washing operations includes decoupling the cross-over setting tool from the lower completion assembly 42, and removing the setting tool along with the connected wash pipe from the wellbore 38. The upper completion assembly 60 can then be installed in the wellbore 38 and coupled to the lower completion assembly 42 to begin fluid production. In this configuration, installing and removing the wash pipe can require a significant amount of time to perform, thereby delaying production operations. Therefore, it may be highly desirable to provide a system that does not require installation and removal of a wash pipe to achieve the washing and/or gravel pack operations. At least one of the benefits of the current disclosure is that a separate wash pipe may not be necessary for washing operations. The current disclosure provides a degradable metal barrier 100 (see FIG. 2) that can be applied to the screen assemblies 48, 52 and 56 for temporarily preventing fluid and pressure communication radially through the screen assemblies (i.e. between an exterior 96 and an interior 94 of the screen assemblies, see FIG. 5). With fluid and pressure communication radially through the screen assemblies 48, 52 and 56 prevented, the lower completion assembly 42 can be used for washing operations without the need for a separate wash pipe. After and/or during washing or gravel pack operations, the degradable metal barrier 100 can be dispersed through degradation, thereby providing fluid and pressure communication radially through the screen assemblies 48, 52 and 56 and allowing operation of screen assemblies for production of wellbore fluids to the platform 10. It should be understood that radially through the screen assemblies refers to a direction between the interior 94 and the exterior 96 of the screen assembly 48, 52, and 56 through layers of the screen assembly. Also, radial flow between the interior 94 and exterior 96 of the screen assembly 48, 52 and 56 can have some lateral displacement (i.e. along a longitudinal axis of the screen assembly) and some axial displacement (i.e. around the longitudinal axis), but the majority of the flow is radially directed, which is generally perpendicular to the longitudinal axis of the screen assembly 48, 52 and 56. Please note that the radially directed flow can also refer to fluids flowing radially through screen layers and traveling longitudinally through drainage layer flow paths 81 to an ICD 87 that can control ingress of the fluids into a flow passage 78.

The screen assemblies 48, 52 and 56 can include wire wound screens, perforated shrouds, wire mesh, etc. which allow wellbore fluids to pass through the assemblies but generally does not allow debris or gravel pack sand contained in the fluid to pass through. Unfortunately, due to damage or clogging of the assemblies 48, 52 and 56 during installation, the assemblies may not provide the desired fluid flow after they are installed in the wellbore 38. The degradable metal barrier 100 of the current disclosure can prevent (or at least minimize) damage and/or clogging of the assemblies during installation and handling, thereby preserving the fluid flow capabilities of the screen assemblies 48, 52 and 56. After installation, the degradable metal barrier 100 can be dissolved, eroded, corroded, or otherwise degraded to remove the barrier. Removing the barrier 100 allows flow fluid through the screen assemblies 48, 52 and 56.

FIG. 2 shows a more detailed partial cross-sectional view of the screen assembly 52 after it has been installed in the wellbore 38. It should be understood that even though the screen assemblies 48 and 56 are not shown, this discussion regarding screen assembly 52 can also apply to them. The screen assembly 52 can be positioned adjacent perforations that extend through the casing 40, the cement 84, and into the earthen formation 14. The screen assembly 52 is interconnected in the tubing string 36 which includes the internal flow passage 78. The centralizers 50 and 54 can be used to maintain the screen assembly 52 proximate the center of the casing 40. However, the centralizers 50 and 54 are not required. For example, one or more of the centralizers 50 and 54 can be absent, and/or replaced with a variety of packers.

The annulus 75 can be formed radially between the tubular string 36 and the casing string 40. A fluid 76 (see FIG. 4) can flow from the formation 14 into the annulus 75 and through the screen assembly 52, which can include a filter layer 85 and an inflow control device (“ICD”) 87. The filter layer 85 prevents or at least reduces the amount of debris, such as gravel, sand, and other particulate matter, from entering the interior flow passage 78. The fluid 76 passing through the filter layer 85 can flow longitudinally between a base pipe 86 and screen layer 85, through the ICD 87, and into the interior flow passage 78 for eventual production to the surface, and/or the fluid 76 passing through the filter layer 85 can flow along flow paths directly to the interior flow passage 78, as can be the case with a perforated base pipe 86. The perforated shroud 92 is shown in a cut-away view that allows the filter layer 85 underneath to be seen. However, it should be clear that the perforated shroud 92 generally extends the length of the filter layer 85 and surrounds the filter layer.

The screen assembly 52 can include the degradable metal barrier 100 in one or more locations. The barrier 100 can be applied to the exterior of the perforated shroud 92 such that it covers all the perforations in the shroud 92. FIG. 2 merely shows a cut-away, but the barrier 100 would preferably extend the length of the shroud 92 and surround the shroud 92, thereby covering all flow paths through the shroud 92. Alternatively, or in addition to, the barrier 100 can also be applied between the shroud 92 and the filter layer 85 as shown by the 2nd cut-away in FIG. 2. The barrier 100 would preferably be extended the length of the filter layer 85 and surround the filter layer 85, thereby covering all flow paths through the filter layer 85. Prior to degrading the barrier 100, fluid and pressure communication through the screen assembly 52 is prevented (or at least significantly restricted). However, after the barrier(s) 100 is degraded, then fluid and pressure communication is permitted through the screen assembly 52.

It should be understood that a degradable metal material 101, which forms the degradable metal barrier 100, can be applied as a coating by spraying, dipping, and/or painting the metal material 101 (see FIG. 8) on a component of the screen assembly to build up the degradable metal barrier 100, and/or as a separate thin sheet of degradable metal material 101 wrapped around the component of the screen assembly 48, 52, 56 being covered. For example, the degradable metal material 101 can be applied by wrapping a thin sheet of degradable metal one or more times around a base pipe 86, filter layer 85, drainage layer, shroud 92, etc. of the screen assembly 48, 52, 56, thereby blocking flow paths through the screen assembly 48, 52, 56 and preventing (or substantially preventing) fluid and pressure communication through the screen assembly 48, 52, 56. Multiple wraps can provide increased time required to degrade the barrier 100 as well as provide increased pressure isolation between the annulus 75 and the flow passage 78. Alternatively, or in addition to, the degradable metal material 101 can be applied by spraying the degradable metal material 101 on the base pipe 86, filter layer 85, drainage layer, shroud 92, etc. of the screen assembly 48, 52, 56, thereby blocking flow paths through the screen assembly 48, 52, 56 and preventing fluid and pressure communication through the screen assembly 48, 52, 56. The thickness of the coating of the degradable metal can determine or at least contribute to a determination of the time necessary to degrade the barrier 100. The coating thickness of the degradable metal can also determine the magnitude of its pressure isolation.

The degradable metal material 101 can be chosen to provide degradation of the metal barrier 100 in a predetermined period of time after the screen assembly 48, 52, 56 has been installed in the wellbore 38. Different degradable metals and/or degradable metal alloys can be used for the material 101 and can provide a range of degradation rates for the barrier 100. The degradation time can also be dependent on the thickness of the barrier 100. A surface coating 102 can be applied to the degradable metal barrier 100 to increase or decrease the degradation rate of the barrier 100. For example, after the metal barrier 100 has been applied to the screen assembly 48, 52, 56 during its assembly process, a surface coating 102 can be applied to a surface of the barrier 100 where the surface coating 102 can inhibit or accelerate degradation of the barrier 100 once the screen assembly 48, 52, 56 has been installed in the wellbore 38. The surface coating 102 can be applied as a coating by spraying, dipping, and/or painting a surface coating material on the degradable metal barrier 100 or as a thin layer of material wrapped around the barrier 100. The surface coating material can be a metal, a polymer, polyurethane, a plastic, a TEFLON® material, a wax, a drying oil, an epoxy, a crosslinked partially hydrolyzed polyacrylic, a silicate material, a glass, an inorganic durable material, polylactic acid, polyvinyl alcohol, polyvinylidene chloride, a hydrophobic material, paint, and any combination thereof.

Degradation of the degradable metal barrier 100 can be caused in many ways, all of which are contemplated by this disclosure. For example, galvanic corrosion can be used to degrade the barrier 100. Additionally, degrading agents, such as acidic or non-acidic fluids, can be delivered to the barrier 100 via the flow passage 78 and/or the annulus 75 to cause degradation of the barrier 100. Downhole wellbore conditions can also cause barrier 100 to degrade.

Galvanic corrosion occurs when two different metals or metal alloys are in electrical connectivity with each other and both are in contact with an electrolyte. As used herein, the phrase “electrical connectivity” means that the two different metals or metal alloys are either touching or in close enough proximity to each other such that when the two different metals are in contact with an electrolyte, the electrolyte becomes electrically conductive and ion migration occurs between one of the metals and the other metal, and is not meant to require an actual physical connection between the two different metals, for example, via a metal wire. It is to be understood that as used herein, the term “metal” is meant to include pure metals and also metal alloys without the need to continually specify that the metal can also be a metal alloy. Moreover, the use of the phrase “metal or metal alloy” in one sentence or paragraph does not mean that the mere use of the word “metal” in another sentence or paragraph is meant to exclude a metal alloy. As used herein, the term “metal alloy” means a mixture of two or more elements, wherein at least one of the elements is a metal. The other element (s) can be a non-metal or a different metal. An example of a metal and non-metal alloy is steel, comprising the metal element iron and the non-metal element carbon. An example of a metal and metal alloy is bronze, comprising the metallic elements copper and tin.

A metal that is less noble, compared to another metal, will dissolve in the electrolyte. The less noble metal is often referred to as the anode, and the more noble metal is often referred to as the cathode. Galvanic corrosion is an electrochemical process whereby free ions in the electrolyte make the electrolyte electrically conductive, thereby providing a means for ion migration from the anode to the cathode—resulting in deposition formed on the cathode. Certain metal alloys, such as a single metal alloy containing at least 50% magnesium, can dissolve in an electrolyte without a distinct cathode being present. Suitable slowly degradable materials that may be used in accordance with the embodiments of the present disclosure include galvanically-corrodible or dissolvable metals and metal alloys. Galvanically-corrodible metals and metal alloys may be configured to degrade via an electrochemical process in which the galvanically-corrodible metal corrodes in the presence of an electrolyte (e.g., brine or other salt-containing fluids present within the wellbore 38). As used herein, an “electrolyte” is any substance containing free ions (i.e., a positively or negatively charged atom or group of atoms) that make the substance electrically conductive. The electrolyte can be selected from the group consisting of, solutions of an acid, a base, a salt, and combinations thereof. A salt can be dissolved in water, for example, to create a salt solution. Common free ions in an electrolyte can include sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl−), bromide (B−) hydrogen phosphate (HPO4 2−), and hydrogen carbonate (HCO3−). Preferably, the electrolyte contains chloride ions. The electrolyte can be a fluid that is introduced into the wellbore 38 or a fluid emanating from the wellbore 38, such as from the earthen formation 14.

Suitable galvanically-corrodible metals and metal alloys include, but are not limited to, gold, gold-platinum alloys, silver, nickel, nickel-copper alloys, nickel-chromium alloys, copper, copper alloys (e.g., brass, bronze, etc.), chromium, tin, aluminum, iron, zinc, magnesium, magnesium alloys, beryllium, and any alloy of the aforementioned materials.

Suitable magnesium alloys include alloys having magnesium at a concentration in the range of about 70% to about 98% by volume of the metal alloy. Magnesium alloys comprise at least one other ingredient besides the magnesium. The other ingredients can be selected from one or more metals, one or more non-metals, or a combination thereof. Suitable metals that may be alloyed with magnesium include, but are not limited to, lithium, sodium, potassium, rubidium, cesium, beryllium, calcium, strontium, barium, aluminum, gallium, indium, tin, thallium, lead, bismuth, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, praseodymium, silver, lanthanum, hafnium, tantalum, tungsten, terbium, rhenium, osmium, iridium, platinum, gold, neodymium, gadolinium, erbium, oxides of any of the foregoing, and any combinations thereof.

Suitable non-metals that may be alloyed with magnesium include, but are not limited to, graphite, carbon, silicon, boron nitride, and combinations thereof. The carbon can be in the form of carbon particles, fibers, nanotubes, or fullerenes. The graphite can be in the form of particles, fibers, or graphene. The magnesium and its alloyed ingredient(s) may be in a solid solution and not in a partial solution or a compound where inter-granular inclusions may be present. In some embodiments, the magnesium and its alloyed ingredient(s) may be uniformly distributed throughout the magnesium alloy but, as will be appreciated, some minor variations in the distribution of particles of the magnesium and its alloyed ingredient(s) can occur.

Suitable galvanically-corrodible metals and metal alloys also include micro-galvanic metals or materials, such as solution-structured galvanic materials. An example of a solution-structured galvanic material is a magnesium alloy containing zirconium (Zr), where different domains within the alloy contain different percentages of Zr. This leads to a galvanic coupling between these different domains, which cause micro-galvanic corrosion and degradation. Micro-galvanically corrodible magnesium alloys could also be solution structured with other elements such as zinc, aluminum, manganese, nickel, cobalt, calcium, iron, carbon, tin, silver, copper, titanium, rare earth elements, etc. Examples of solution-structured micro-galvanically-corrodible magnesium alloys include ZK60, which includes 4.8% to 6.2% zinc, minimum 0.45% zirconium, 0% to 0.3% other, and balance magnesium; AZ80, which includes 7.8% to 9.2% aluminum, 0.2% to 0.8% zinc, 0.12% manganese, 0.015% other, and balance magnesium; and AZ31, which includes 2.5% to 3.5% aluminum, 0.7% to 1.3% zinc, 0.2% manganese, 0.15% other, and the balance magnesium.

FIG. 3 shows the screen assembly 48 after it has been installed in the wellbore 38 proximate perforations in the casing 40. In this configuration, fluids 77 (e.g. a slurry) can be pumped through the annulus 75 proximate the screen assemblies 48, 52, 56. Because the degradable metal barrier 100 has not yet been degraded, fluid does not flow radially through the screen assemblies 48, 52, 56 into the flow passage 78. Instead, the fluid 77 continue flowing along the annulus 75 until a path into the passage 78 is provided (such as past the deepest screen assembly) where the fluid 77 may enter the passage 78 and carry debris through the passage up to the platform 10.

When a washing operation is complete, and it is desired to allow radial fluid flow through the screen assembly 48, 52, 56 from the annulus 75 into the passage 78, the metal barrier(s) 100 can be degraded. During and/or after degradation of the barriers 100, the fluid 77 can represent a gravel laden slurry used to carry gravel to the perforations and to the annulus external to the screen assemblies 48, 52, 56, where the gravel is deposited in the annulus, the screen assemblies 48, 52, 56, and perforations to form a gravel pack. Once the gravel is deposited from the slurry, a remaining carrier fluid 79 can be flowed through the passage 78 to the platform 10.

FIG. 4 shows the screen assemblies 48, 52, 56 after the degradable metal barrier(s) 100 are degraded. The flow paths in the shroud 92 and the filter layer 85 beneath are unobstructed by the barrier(s) 100 and fluid 76 from the earthen formation 14 can flow from the perforations, radially through the screen assemblies 48, 52, 56 and into the flow passage 78, and to the platform 10 for processing.

FIGS. 5-7 show various embodiments of screen assemblies 48, 52, 56 that can utilize the principles of this disclosure. FIG. 5 shows a detailed view of an example embodiment of the screen assembly 48, 52, 56. Please note that the screen assembly does not include a perforated shroud 92. The screen assembly 48, 52, 56 can include a perforated base pipe 86 with supports 90 positioned on an exterior surface of the base pipe 86, and with wire wrapped around the supports 90 to form the filter layer 85. Channels in a drainage layer 80 can be formed between the base pipe 86 and the wrapped wire to allow fluid 76 to flow through the filter layer 85, possibly along an exterior of the base pipe 86, and through a perforation of the base pipe 86 into the interior flow passage 78. Flow paths 81, which can provide radial fluid flow through the screen assembly 48, 52, 56, are indicated as spaces between adjacent wire wraps of the filter layer 85 and perforations in the base pipe 86. Flow paths 81 would also be included in other layers in addition to those shown in FIG. 5, such as a shroud 92, drainage layers 80, 82, etc. As shown by the cut-away areas, the degradable metal barrier 100 can be applied to interior and/or exterior surfaces of the base pipe 86, as well as an exterior surface of the filter layer 85, as well as other layers in the screen assemblies. A surface coating 102 can be applied to the degradable metal barrier 100 to increase or decrease the degradation rate of the barrier 100.

FIG. 6 shows a detailed view of another example embodiment of the screen assemblies 48, 52 and 56. The screen assembly 48, 52, 56 can include a portion of the flow passage 78 through an interior 94 of the screen assembly. In this example, the perforated shroud 92 extends the length of the filter layer 85 and surrounds the filter layer 85. The filter layer 85 is a wire mesh positioned over a wire wound structure with supports 90 positioned on an exterior surface of the base pipe 86. The supports 90 and wire wound structure can form a drainage layer 80 as seen in the expanded view. A degradable metal barrier 100 can be applied to the various components in the assembly 48, 52 and 56 at the positions shown as a thin metal sheet, and/or as a coating sprayed, dipped and/or painted on the surfaces to build up the degradable metal barrier 100 in one or more of these positions. Example positions for the degradable metal barrier 100 are indicated as 1) external to the shroud 92, 2) between the shroud 92 and the filter layer 85, 3) between the filter layer 85 and the drainage layer 80, and 4) between the drainage layer 80 and the base pipe 86. The degradable metal barrier 100 can also be sprayed, dipped and/or painted at these positions which can include infusion of the degradable metal barrier 100 into flow passages through the layers of the screen assembly 48, 52, 56, thereby at least filling a portion of the flow paths 81 with the degradable metal. Again, once the screen assembly 48, 52 and 56 is installed in the wellbore 38, the degradable metal barrier 100 can be degraded away to provide free flow of fluid through the assemblies from the exterior of the assemblies 96 (or annulus 75) to the interior 94 (or flow passage 78).

FIG. 7 shows a detailed view of another example embodiment of the screen assemblies 48, 52 and 56. In this example, the assembly 48, 52 and 56 is surrounded by a gravel pack 88. The perforated shroud 92 again extends the length of the filter layer 85 and surrounds the filter layer 85. The filter layer 85 is shown as a single wire mesh, but it should be understood that several wire mesh layers can be included. A drainage layer 80 (not shown) can be below the filter layer 85. Example positions for the degradable metal barrier 100 are similar to those of FIG. 6 and are 1) external to the shroud 92, 2) between the shroud 92 and the filter layer 85, 3) between the filter layer 85 and the drainage layer 80 (not shown), and 4) between the drainage layer 80 and the base pipe 86. The degradable metal barrier 100 can also be sprayed, dipped and/or painted at these positions which can include infusion of the degradable metal barrier 100 into flow passages through the layers of the screen assembly 48, 52, 56, thereby at least filling a portion of the flow paths 81 with the degradable metal material 101. Again, once the screen assembly 48, 52 and 56 is installed in the wellbore 38, the degradable metal barrier 100 can be degraded away to provide free flow of fluid through the assemblies 48, 52, 56 from the exterior 96 (or annulus 75) to the interior 94 (or flow passage 78).

FIG. 8 shows an example of a layer construction that can be used for any of the embodiments of screen assemblies 48, 52 and 56. The perforated base pipe 86 is positioned radially inward from the other screen assembly layers. This example includes two drainage layers 80, 82 with each being a woven-type wire mesh positioned adjacent each other on an exterior of the base pipe 86 (please note, other drainage layers can be used instead of or in addition to either one of these mesh layers 80, 82, such as a wire wrapped filter layer 85 or an inner shroud drainage layer, etc.). The pore sizes of each drainage layer 80, 82 can be substantially the same, or they can be different sizes, as seen in FIG. 8. A smaller pore size wire mesh can be used for the filter layer 85 and can be positioned radially outward from the drainage layers 80, 82. The perforated shroud 92 can be positioned radially outward from the filter layer 85. Other configurations may position larger pore size wire mesh layers between the shroud 92 and the filter layer 85 to filter out larger debris from the fluid 76 (or slurry 77) prior to the filter layer 85. Example positions for the degradable metal barrier are 1) external to the shroud 92, 2) between the shroud 92 and the filter layer 85, 3) between the filter layer 85 and the drainage layer 80, 4) between the drainage layer 80 and the drainage layer 82, and 5) between the drainage layer 82 and the base pipe 86. The degradable metal barrier 100 can formed by applying a degradable metal material 101 to a component, such as 80, 82, 85, 86, 92, by the material being sprayed, dipped and/or painted at these positions which can include infusion of the degradable metal barrier 100 into flow paths 81 (e.g. pores, perforations, etc.) through the components (or layers) of the screen assembly 48, 52, 56, thereby at least filling a portion of the flow paths 81 with the degradable metal material 101.

Thus, a system for temporarily preventing fluid flow through a screen assembly installed in a wellbore 38 has been described. Embodiments of the system may generally include a screen assembly 48, 52, 56 with components that may include at least a base pipe 86 and a filter layer 85, with flow paths 81 through each of the components. The system can include a degradable metal barrier 100 that is applied to at least one of the components, which thereby temporarily prevents fluid flow through the flow paths 81, and temporarily provides pressure isolation between an interior 94 and an exterior 96 of the screen assembly 48, 52, 56, wherein degradation of the metal barrier 100 allows fluid and pressure communication between the interior 94 and the exterior 96 of the screen assembly 48, 52, 56.

For any of the foregoing embodiments, the system may include any one of the following elements, alone or in combination with each other:

The degradation of the degradable metal barrier 100 can result 1) from a period of time the degradable metal barrier 100 is exposed to a downhole environment, 2) from a degrading agent placed in contact with the degradable metal barrier, and/or 3) from any one of corrosion, erosion, dispersion, dissolution, hydrolytic degradation, chemical reactions, thermal reactions, and reactions induced by radiation.

The components of the screen assembly 48, 52, 56 can also include at least one drainage layer 80, 82. The system can also include a surface coating 102 applied to the degradable metal barrier 100, thereby either increasing or decreasing a rate of degradation of the degradable metal barrier 100. The surface coating 102 can be a metal, a polymer, a polyurethane, a plastic, a TEFLON® material, a wax, a drying oil, an epoxy, a crosslinked partially hydrolyzed polyacrylic, a silicate material, a glass, an inorganic durable material, polylactic acid, polyvinyl alcohol, polyvinylidene chloride, a hydrophobic material, paint, and any combinations thereof.

The degradable metal barrier 100 can include a degradable metal material 101 that is applied to the component by at least one of 1) the material 101 sprayed on the component, 2) the material 101 painted on the component, and 3) the component dipped in the material 101. The degradable metal barrier 100 can be a thin sheet of degradable metal material 101 that is applied to the component by being wrapped around the component such that the thin sheet blocks the flow paths 81 through the component. The component of the screen assembly 48, 52, 56 can be one of the base pipe 86, the drainage layer 80, 82, the filter layer 85, and a shroud 92.

Additionally, a method of temporarily preventing fluid flow through a screen assembly 48, 52, 56 installed in a wellbore 38 has been described. Embodiments of the method may generally include interconnecting the screen assembly 48, 52, 56 in a tubing string 36, where components of the screen assembly can include at least a base pipe 86 and a filter layer 85, with flow paths 81 through each of the components. The method can include applying a degradable metal barrier 100 to at least one of the components, temporarily preventing fluid flow through the flow paths 81, thereby temporarily preventing fluid and pressure communication between an interior 94 and an exterior 96 of the screen assembly 48, 52, 56, installing the screen assembly 48, 52, 56 in the wellbore 38, degrading the degradable metal barrier 100 in the wellbore 38, and allowing fluid and pressure communication between the interior 94 and the exterior 96 of the screen assembly 48, 52, 56 in response to the degrading.

For the foregoing embodiments, the method may include any one of the following steps, alone or in combination with each other:

The degrading of the degradable metal barrier 100 can result 1) from a period of time the degradable metal barrier 100 is exposed to a downhole environment, 2) from a degrading agent placed in contact with the degradable metal barrier 100, and/or 3) from any one of corrosion, erosion, dispersion, dissolution, hydrolytic degradation, chemical reactions, thermal reactions, and reactions induced by radiation.

The components of the screen assembly 48, 52, 56 can also include at least one drainage layer 80, 82. The method can include applying a surface coating 102 to the degradable metal barrier 100, thereby either increasing or decreasing a rate of degradation of the degradable metal barrier 100. The surface coating 102 can be a metal, a polymer, a polyurethane, a plastic, a TEFLON® material, a wax, a drying oil, an epoxy, a crosslinked partially hydrolyzed polyacrylic, a silicate material, a glass, an inorganic durable material, polylactic acid, polyvinyl alcohol, polyvinylidene chloride, a hydrophobic material, paint, and any combinations thereof.

The degradable metal barrier 100 can be formed by applying a degradable metal material 101 to the component by at least one of 1) the material 101 sprayed on the component, 2) the material 101 painted on the component, and 3) the component dipped in the material 101. The degradable metal barrier 100 can also be formed by applying a thin sheet of degradable metal material 101 to the component by wrapping the thin sheet around the component such that the thin sheet blocks the flow paths 81 through the component. The component of the screen assembly 48, 52, 56 can be one of the base pipe 86, the drainage layer 80, 82, the filter layer 85, and a shroud 92.

Although various embodiments have been shown and described, the disclosure is not limited to such embodiments and will be understood to include all modifications and variations as would be apparent to one skilled in the art. Therefore, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed; rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims. 

1. A system for temporarily preventing fluid flow through a screen assembly installed in a wellbore, the system comprising: a screen assembly configured to interconnect in a tubing string, with components of the screen assembly comprising: a base pipe, and at least one filter layer, with flow paths through each of the base pipe and the filter layer; and a degradable metal barrier that is applied to at least one of the components, which thereby temporarily prevents fluid flow through the flow paths, and temporarily provides pressure isolation between an interior and an exterior of the screen assembly, wherein degradation of the metal barrier allows fluid and pressure communication between the interior and the exterior of the screen assembly.
 2. The system according to claim 1, wherein the degradation is a result of a period of time the degradable metal barrier is exposed to a downhole environment.
 3. The system according to claim 1, wherein the degradation is a result of a degrading agent placed in contact with the degradable metal barrier.
 4. The system according to claim 1, wherein the degradation is a result of at least one selected from a group consisting of corrosion, erosion, dispersion, dissolution, hydrolytic degradation, chemical reactions, thermal reactions, and reactions induced by radiation.
 5. The system according to claim 1, wherein the components of the screen assembly further comprise at least one drainage layer.
 6. The system according to claim 1, further comprising a surface coating applied to the degradable metal barrier, thereby either increasing or decreasing a rate of degradation of the degradable metal barrier.
 7. The system according to claim 6, wherein the surface coating is selected from the group consisting of a metal, a polymer, a polyurethane, a plastic, a TEFLON® material, a wax, a drying oil, an epoxy, a crosslinked partially hydrolyzed polyacrylic, a silicate material, a glass, an inorganic durable material, polylactic acid, polyvinyl alcohol, polyvinylidene chloride, a hydrophobic material, paint, and any combinations thereof.
 8. The system according to claim 1, wherein the degradable metal barrier comprises a degradable metal material that is applied to the at least one component by one of the group consisting of the material sprayed on the at least one component, the material painted on the at least one component, and the at least one component dipped in the material.
 9. The system according to claim 1, wherein the degradable metal barrier comprises a thin sheet of degradable metal material, and wherein the thin sheet is applied to the at least one component by being wrapped around the at least one component such that the thin sheet blocks flow passages through the at least one component.
 10. The system according to claim 9, wherein the at least one component is selected from a group consisting of the base pipe, a drainage layer, the filter layer, and a shroud.
 11. A method of temporarily preventing fluid flow through a screen assembly installed in a wellbore, the method comprising: interconnecting the screen assembly in a tubing string, wherein components of the screen assembly comprise: a base pipe, and at least one filter layer, with flow paths through each of the base pipe and the filter layer; and applying a degradable metal barrier to at least one of the components; temporarily preventing fluid flow through the flow paths, thereby temporarily preventing fluid and pressure communication between an interior and an exterior of the screen assembly; installing the screen assembly in the wellbore; degrading the degradable metal barrier in the wellbore; and allowing fluid and pressure communication between the interior and the exterior of the screen assembly in response to the degrading.
 12. The method according to claim 11, wherein the degrading is a result of a period of time the degradable metal barrier is exposed to a downhole environment.
 13. The method according to claim 11, wherein the degrading is a result of a degrading agent placed in contact with the degradable metal barrier.
 14. The method according to claim 11, wherein the degrading is a result of at least one selected from a group consisting of corrosion, erosion, dispersion, dissolution, hydrolytic degradation, chemical reactions, thermal reactions, and reactions induced by radiation.
 15. The method according to claim 11, wherein the components of the screen assembly further comprise at least one drainage layer.
 16. The method according to claim 11, further comprising applying a surface coating to the degradable metal barrier, thereby either increasing or decreasing a rate of degradation of the degradable metal barrier.
 17. The method according to claim 16, wherein the surface coating is selected from the group consisting of a metal, a polymer, a polyurethane, a plastic, a TEFLON® material, a wax, a drying oil, an epoxy, a crosslinked partially hydrolyzed polyacrylic, a silicate material, a glass, an inorganic durable material, polylactic acid, polyvinyl alcohol, polyvinylidene chloride, a hydrophobic material, paint, and any combinations thereof.
 18. The method according to claim 11, further comprising forming the degradable metal barrier by applying a degradable metal material to the at least one component by one of the group consisting of spraying the material on the at least one component, painting the material on the at least one component, and dipping the at least one component in the material.
 19. The method according to claim 11, further comprising forming the degradable metal barrier by applying a thin sheet of degradable metal material to the at least one component by wrapping the thin sheet around the at least one component such that the thin sheet blocks flow paths through the at least one component.
 20. The method according to claim 19, wherein the at least one component is selected from a group consisting of the base pipe, a drainage layer, the filter layer, and a shroud. 